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A Pine Siskin, a regular but unpredictable visitor in winter in South Dakota Research shows that southward irruptions of boreal finches such as Pine Siskins may be predicted from recent seasonal climate records.

Not a lot of time this week to blog, as I’ve been in pretty intense meetings all week for work. However, it was through those meetings that I became aware of this interesting research paper. Birders are always wondering when that next great “irruption” of boreal bird species will occur. On occasion, boreal finches such as Common Redpolls, Pine Siskins, and Crossbills will move southward in great numbers from their boreal forest stronghold. The thought is that such irruptions occur when poor “mast” production occurs, with lower conifer seed numbers than normal. The birds thus move southward in search of food.

It’s not just boreal finches that are subject to occasional southward irruptions. One of the greatest birding experiences of my life was during the huge boreal owl irruption into northern Minnesota over a decade ago, when Great Grey Owls and Northern Hawk Owls were seemingly “dripping off the trees”. Those irruptions are thought to be due to a similar driving force…a loss of a primary food source…with periodic crashes of small rodent populations driving the owls southward in search of food for the winter.

The paper below (click to see it) gives an assessment of climate data to potentially predict when a finch irruption would occur. The species studied here is the Pine Siskin, but the authors note that it may also apply for other boreal finch species that depend on conifer mast. Cool study…

More coming next week! Given I’m still in meetings the rest of the week and have family obligations all weekend, it’s likely the next blog post won’t come until Monday! Click below for the study…